Extension table with pin and groove slides



April 10, 1951 A. DE GAAL EXTENSION TABLE WITH PIN AND GROOVE SLIDES Filed June 18, 1947 \NVENTOR.

Patented Apr. 10, 1951 UNITED STATES PATENT" 'oFF1-cr. 7

EXTENSION TABLE WITH PIN AND GROOVE SLIDES Abris De Gaal, Manhassett, N. Y.

Application June 18, 1947, Serial No. 755,280

' 1 Claim. 1

This invention relates to extension tables. More particularly it relates to a sliding structure for guiding and positioning the two sections of the table top for relative movement.

Tables of this type generally are constructed to permit the two halves of the table top to be moved apart and extra leaves inserted in the intervening space so that a larger surface area may be made available as the occasion requires.

Such tables are usually arranged with adjacent wooden sliding members having tongue and groove construction so that the area of the contacting surfaces, which slide relative to each other, is large. With such construction any distortion of the slide members, such as would be occasioned by slight swelling, shrinking or warping, causes the members to bind or stick and makes opening or closing of the table extremely difficult. This invention is concerned with the arrangement and construction of the slides that guide the movement of the table top, and with the storage of the extra leaves,

It is, accordingly, an object of this invention to provide an improved extendible table having bearing surfaces so constructed as to insure minimum friction between the moving parts and their precise relative alignment.

It is a further object to provide such a table in which the ease of movement between the respective parts is not affected adversely by the normal swelling or shrinking of the wooden members under various conditions of use and over long periods of time.

It is a further and more specific object to provide a draw-top table so constructed that each sliding surface makes its respective contact along a single line substantially perpendicular to the direction of motion.

It is another specific object to provide a drawtop table wherein slidable bearing surfaces are so constructed as to maintain precision alignment between respective moving components.

It is still another object to provide a slide structure for such a table having fixed and floating slide members wherein the floating slide member is supported and positioned by alignment and bearing pins extending between said members and longitudinal grooves in adjacent members and adapted to move therealong.

It is a more specific object, of the invention to provide such a sliding structure having two fixed slides and a floating slide therebetween which is maintained in proper spaced relationship and alignment by horizontally and vertically ,2 extending pin members between the fixed and floating slides.

Other objects and advantages of the present invention will be apparent from the following description considered in conjunction with the attached drawings in which:

Figure 1 shows an extension table (in the open position) incorporating my invention;

Figure 2 is a planview of one of the slide structures (with the slide members laterally separated) of the table in the closed position;

Figure 3 is a plan view showing the slide structure in extended position;

Figure 4 is an enlarged secticnal view taken along line 4-4 of Figure 2; and 1 Figure 5 is a perspective view showing the relationship of the fixed and floating slides.

In order to control the direction of the relative motion between the table top portions 2 and 4 (Figure 1), two or more sets of guide assemblies, generally indicated at 6, are carried by the underside of the .tabletop. Each guide assembly includes afixed slide 8 secured to a table top portion 2 or 4 by any suitable means, as for example screws I! (Figure 4), and cooperates with a fixed slide l4 secured to-the other table top portion :by suitable means .(not shown),as for example screws.--

In order to maintain proper alignment and prevent binding of the fixed slides 8 and I4 when in the extended position, a floating slide I8 is interposed between them and arranged to overlap the fixed slides and so assist in maintaining proper. alignment under all conditions of operation. In order to support the floating slide l8, cylindrical bearing pins are arranged to extend horizontally from one slide. into corresponding grooves in the adjacent slide. Such a bearing pin 22, which in the preferred embodiment is constructed of steel, but may be of wood or other suitable material, is secured, as shown in Figure 4, by'press fitting or other suitable means, in the floating slide lB'and extends into, and is arranged to slide along the lower surface of,-a groove 24, in the fixed slide 14. A similar bearing pin 26, is secured in fixed slide 8 and arranged to extend'into, and slide along the upper surface of, a groove 28 extending along the adjacent side or the'floating slide 48. The arrangement of these pins makes it unnecessary to out two oppoSeddohgitudinal slots in'the floating slide 13, thus permittingthe use of a lighter member than would otherwise be required:

- In order to minimize the increased frictional drag that would be occasioned 'byslighdwarping or swelling of the slide members, the grooves 24 and 28 have sufficiently larger cross-sectional dimensions than the bearing pins 22 and 25 to provide suitable clearance under all conditions of operation and over long periods of time.

The pins 22 and 26 thus act as slide bearings, making contact with the opposing surfaces along a single longitudinal line on the surface of the pins. Accordingly, the sliding friction will be low provided the floating slide l8 does not make direct surface contact with either of the fixed slides 8 or H. In order to prevent such contact, vertical spaces, as at 32 and 34, are provided and maintained between the floating and fixed slides by two vertically extending alignment pins 35 and 38, the lower ends of which are rigidly imbedded in a sub-base 42, secured to floating slide l8 by suitable means, as for example screws Ml. These pins extend upwardly into longitudinal grooves 46 and 48 in the lower surfaces of the fixed slides l4 and 8, respectively. As before, the grooves 46 and 48 have slightly larger cross sectional dimensions than the alignment pins to prevent binding which might be caused by slight swelling, shrinking, or warping of the wooden members. These alignment pins 36 and 38 thus are adjusted to slide along grooves 46 and 48 as the table is .extended or retracted and maintain .the desired lateral positioning of the floating slide l8 relative to the fixed slides 8 and M. It may be seen that each sliding contact in the structure is between asmooth, fiat surface and a longitudinal line along the face of a cylindricallyshaped bearing or alignment pin.

Slide covers 52 and 54 are secured, respectively, to the outer surfaces of fixed slides l4 and 8, as by screws 56, and extend downwardly along the sides, but arespaced suitably-from the sub-base 42 so as not to interfere with the sliding move-- ment. I

The number of alignment and bearing members to be used in each guide assembly will depend upon such factors as the lengths of the slide members, the amount of extension required and the precision of manufacture. The guide assembly shown in Figures 2 and 3 has four horizontally extending bearing pins and four vertical alignment pins; cooperating with each pin is a corresponding groove. Some or all of thegrooves preferably are cut to :the exact length which is required'bythe amount of extension in the particular application; thus the movement of the table .top portions is limited by the abutting of the pins against the ends of the corresponding grooves, as for example at 55 in Figure 3. In

this example each of the grooves is slightly longer Cdepending-uponthe diameter of the pins) than .one half of the ,maximum extension movement of the guide assembly.

To permit convenient storage of extra leaves,

such as 51, within the table when it is in the vertical space :of sufficient depth to hold several table leaves is provided'between the upper surface of the-platform 58;and the lower surfaces of the table top portions 2 and 4.

In orderto prevent "the table leaves from slid- .ing beyond :the ends of the platform 58, upright extensions 63, :(Figure 4) and 64-, (Figure 1) are :secured to the-platform at eachend, as by screws 66.

"The center portion. of upright extension 64 is cut away to permit, in conjunction with a cutout 68 in platform 58, easy removal of the extra leaves.

Thus it will be seen that I have provided a table slide construction which may include any required number of slide assemblies which will permit the easy opening and closing of the table top sections for the expansion and contraction of the effective table top area, and wherein each slide assembly includes a slide member secured to each of the table top sections and an intervening floating slide member which is supported by the fixed slide members and is centered between the latter in such a manner that the floating action will always be maintained, thus preventing binding and excessive friction between the members of the slide assembly.

More specifically I have provided pins which are carried by certain of the slide members and operate within grooves or slots in the complementary slide and which have line contact with the walls of the grooves, thus minimizing materially the sliding friction.

Additionally, I have so related the pins and lots to the slide members that the latter may be made relatively light and yet with normal distortion during use will produce no bindin action which will interfere with the opening and closing of the table top.

Moreover, I have so arranged these slide assemblies in relation to the table top members, that a space is provided for the storage of the extra leaves, and I have provided a means for maintaining the extra leaves in proper storage positions for easy removal.

While I have described a particular construction or embodiment of my invention, this has not been for the purpose of limitation, and I therefore do not wish to be limited to the particular structure shown and described, except in so far as limitation i made necessary by the claim. It will be obvious to those skilled in the art that many changes of form may be made Without departing from the spirit of the invention or without exceeding the scope of claim.

I claim:

In an extensible table having two relatively movable top portions, a slide structure for use in extending or shortening the table comprising, in combination, a first fixed slide secured to one table top portion and extending beyond the edge thereof. a second fixed slide secured to a second table top portion and extending beyond the edge thereof in overlapping relation to said first fixed slide, a floating slide extendin longitudinaliy of and spaced betweensaid fixed slides and movable relative thereto and unattached to either of said movable table top portions, said fixed slides having vertical longitudinal grooves in the lower faces thereof, said first fixed slide having a longitudinal groove in the face thereof adjacent said floating slide and said floating slide having a horizontal longitudinal groove in the face thereof adjacent said second fixed slide, horizontal cylindrical bearing pins rigid, respectively, with said floating slide and said second fixed slide and extending into the adiaccnt horizontal grooves in said first fixed slide and said floating slide, respectively, and freely movable in said grooves, said cylindrical pins having line contact only with said slides in said horizontal grooves, a base plate secured to the lower surface of said floating slide, and vertical cylindrical pins secured to said base plate and extendinginto said vertical grooves and freely movable therein 5 and having line contact only with said fixed slides Number in said vertical grooves. 166,679 ABRIS DE GAAL. 387,149 468,042 REFERENCES CITED 540,483- The following references are of record in the 1, file of this patent: 1,055,647 UNITED STATES PATENTS 1 233 232 Number Name Date 1 2:1 3: 2

75,022 Jenkins Mar. 3, 1868 104,340 Olds June 14, 1870 Name Date Bent Aug. 1'7, 1875 Craig July 31, 1888 Holstein Feb. 2, 1892 Comstock June 4,1895 Durgin May 4, 1897 Murdock Mar. 11, 1913 Lundeen May 25, 1926 Lundeen Sept. 28, 1926 Orsenigo May 24, 1938 

